As mobile device technology continues to develop and demand therefor continues to increase, demand for secondary batteries as energy sources is rapidly increasing. Among these secondary batteries, research on lithium secondary batteries, which exhibit high energy density and discharge voltage, is underway and such lithium secondary batteries are commercially available and widely used.
In general, secondary batteries have a structure in which an electrode assembly including a cathode, an anode, and a separator disposed therebetween is accommodated in a stacked or wound form in a battery case made of a metal can or a laminate sheet and an electrolyte is injected thereinto or the electrode assembly is impregnated with an electrolyte.
These secondary batteries undergo increase in volume due to anode expansion, gas generation, or the like when in use and the amount of an electrolyte is gradually decreased due to side reactions of an anode and electrolyte oxidation at a cathode, which results in deteriorated battery lifespan.
Therefore, there is an urgent need to develop a novel lithium secondary battery that addresses the problems described above.